Acute myocardial infarction in patients with syncope
Daniel McDermott1, James V Quinn, Charles E Murphy
1Department of Emergency Medicine, University of California, San Francisco, California 94143-0208, United States. dmcderm@medicine.ucsf.edu
CJEM
|March 11, 2009
Summary
The incidence of acute myocardial infarction (AMI) in emergency department patients with syncope is low. A normal electrocardiogram (ECG) is highly effective at ruling out AMI, but its sensitivity is limited.
Area of Science:
- Emergency Medicine
- Cardiology
- Diagnostic Accuracy
Background:
- Syncope is a common presentation in emergency departments.
- Distinguishing cardiac from non-cardiac causes of syncope is crucial for patient management.
- Acute myocardial infarction (AMI) is a critical diagnosis to exclude in syncope patients.
Purpose of the Study:
- To determine the incidence of AMI in emergency department patients presenting with syncope.
- To characterize the clinical features of AMI in this population.
- To evaluate the diagnostic utility of the initial electrocardiogram (ECG) for identifying AMI in syncope patients.
Main Methods:
- Prospective cohort study of consecutive patients presenting with syncope.
- Initial ECGs were analyzed using a prespecified definition for abnormality.
- Patients were followed for 30 days to ascertain AMI diagnosis.
Main Results:
- AMI was diagnosed in 3.1% of 1474 syncope patients.
- Most AMI cases (80%) did not present with ST-segment elevation.
- Initial ECG had 80% sensitivity and 64% specificity for AMI, with a 99% negative predictive value.
Conclusions:
- The incidence of AMI in patients with syncope is low.
- A normal ECG is valuable for excluding AMI due to its high negative predictive value.
- The sensitivity of the initial ECG for detecting AMI in syncope patients is limited.
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